Sanz-Hernández, D. Hierro-Rodriguez, A. Donnelly, C. Pablo-Navarro, J. Sorrentino, A. Pereiro, E. Magén, C. McVitie, S. De Teresa, J.M. Ferrer, S. Fischer, P. Fernández-Pacheco, A. Artificial Double-Helix for Geometrical Control of Magnetic Chirality ACS Nano 10.1021/acsnano.0c00720 2020 2020